When is a low-carb diet not just a low-carb diet? When there’s a different name to it. And with the popularity of low-carb living for purported weight loss and health benefits, many people are turning to the diet in all its various forms. Because most Americans eat more than 200 grams (g) of carbohydrates per day, dipping lower than that is going to be, in a form, a lower-carb diet, says Kelly Schmidt, RD, LDN, a nutrition consultant in Columbus, Ohio.
Indeed, the Mayo Clinic points out that carbohydrates ought to make up 45 to 65 percent of an individual’s daily calories. In a 2,000-calorie diet, this means a typical person takes in 900 to 1,300 calories from carbs, or 225 to 325 g of carbs, per day.
The low-carb trend isn’t slowing down, and some research suggests that eating that way does help people lose weight — at least in the short-term. However, some researchers are warning that it may not be safe as a permanent eating approach. In one study, researchers concluded that people who ate the least amount of carbs had the highest risk of death from cardiovascular disease, stroke, and cancer.
Those findings are something to consider if you’re thinking about going on a low-carb diet. And, if you’re set on starting one, know that there are many different types, from the ketogenic diet to the Dukan diet. Yet the name isn’t the biggest thing that matters. “You can put a label on the type of low-carb diet you want to do, but the bottom line — and one reason low-carb diets can be so successful — is you should focus on eating more real food than not,” adds Schmidt.
Right off the bat, know that many of the fad low-carb diets lack research. Therefore, many of their so-called benefits aren’t proven and may be based only on some individuals’ reported experience. With those limitations in mind, here’s a look at 12 popular low-carb plans and how they work:
1. A Basic Low-Carb Diet
There’s no official guideline that defines a low-carb diet, says Schmidt. But generally speaking, consuming about 50 to 100 g of carbs a day is considered a basic low-carb diet, she says. That said, it can be more — it’s all about eating fewer carbs than is normal for you. The perk of this plan is it’s individualized, allowing you to eat the amount that best meets your body’s needs. It also gives you leeway to choose what carbs you want to include (fruits, vegetables, dairy, whole grains, nuts, legumes, and seeds), rather than being on a plan that tells you what you need to eat and when. It’s best for someone who likes that freedom and doesn’t want to spend the time counting grams of carbs.
There may be benefits to following this traditional plan. One study put obese adults who had metabolic syndrome (a cluster of risk factors, like high blood pressure, high blood sugar, and excess belly fat, which increase the risk of cardiovascular disease and type 2 diabetes, as the Mayo Clinic notes) on low-, moderate-, or a high-carbohydrate diet for four weeks. Those in the low-carb group decreased their triglycerides, improved “good” HDL cholesterol, and improved measures of their “bad” LDL cholesterol, whether they lost any weight or not.
2. The Ketogenic, or ‘Keto,’ Diet
This is one of the strictest ways to do a low-carb diet because it limits you to eating foods that altogether fall under 50 g of carbs per day, though some experts recommend going to less than 30 or 20 g, says Franziska Spritzler, RD, CDCES, a low-carb dietitian who’s based in Hollywood, Florida. (Specifically, she says most people need to stay under 30 g, but some active folks can go a bit higher.) You’ll also be eating a significant amount of fat — up to 80 percent of your diet.
A keto diet shifts your body’s fuel-burning engine from one that relies on carbs for energy to one that incinerates fat. A major draw here is that you may lose a significant amount of weight quickly, and that can be initially motivating to see those results so quickly. The downside is that it’s a very limiting diet — you’re eating mostly sources of fat, plus a little protein, and some nonstarchy veggies — so it’s difficult to keep up, and it’s typically intended as a short-term diet, not a lifelong change.
One research review noted that keto diets produce slightly more weight loss compared with a low-fat diet (“slightly more” being about 4.4 pounds, on average), but these results probably won’t last. In the study, after about five months, keto dieters begin to regain the weight they lost.
3. A Low-Carb, High-Fat Diet
This sounds similar to keto, but on this plan, you generally eat more carbs (so your body won’t be in the fat-burning state of ketosis, as it is during keto) and less fat. Carbs might make up about 25 percent of your calories, while fat accounts for over 60 percent. The good news here is that while the keto diet is so strict that it’s difficult for many dieters to stick to it, a more liberal carb allotment (100 to 150 g of carbs a day) is “more practical,” researchers have argued. That said, these researchers also noted that while low-carb, high-fat diets do help people lose weight, the long-term health benefits or risks are unknown, and more research needs to be done.
Many people do this type of low-carb diet for performance benefits during a workout. Proponents say it can teach your body to use fat for fuel, thereby providing a longer-lasting form of energy during extended bouts of endurance activities. That said, whether this diet really does boost performance is still up in the air, suggested one study. If you’re an athlete interested in this style of eating, your best bet is to consult with a registered dietitian who specializes in sports nutrition to see what’s right for you.
4. The Atkins Diet
When it comes to the low-carb craze, the Atkins diet started it all. “Dr. Atkins saw very early on that cutting back on carbs and allowing unlimited protein and fat had such a big impact on appetite and insulin levels,” says Spritzler.
On this plan, you start with a very-low, ketogenic-like intake and then gradually re-add carb sources, like vegetables and fruit. Spritzler notes that one common error is adding back in too many carbs, gaining weight, and then thinking the diet isn’t working. For instance, when you’re in maintenance mode, you probably shouldn’t be eating bread.
That said, this diet also features prepackaged foods and snacks, which are going to be processed fare, regardless of the label “low carb.” The best way to do this diet is to stick to eating whole foods, says Spritzler. As for how effective it is when stacked up against other diets, it may be the most effective — at least in the short-term. People following Atkins lost about 22 pounds in six months, per one meta-analysis.
5. Modified Atkins, Modified Keto Diet
A modified Atkins diet requires eating 10 percent of calories from carbohydrates, 30 percent from protein, and 60 percent from fat. Most research on this diet has been focused on its effectiveness in treating epilepsy, but some people are moving toward this more “moderate” approach for weight loss. “Keto means that you’re in ketosis. For many people, 10 percent carbs won’t allow them to be in that metabolic state, and this is more of a low-carb diet for them. For some it will,” says Ginger Hultin, RD, a Seattle-based integrative registered dietitian. If your goal is to get into ketosis, you should be working with a registered dietitian to make sure you’re eating the right ratio of macronutrients (carbs, protein, and fat) to get there, or monitoring your blood ketones.
6. Low-Carb Paleo
The caveman-eating style focuses on eating fat and protein with fewer carbs. That said, just because you cut out grains, legumes, beans, sweets, and dairy doesn’t make it automatically low-carb, as you can still eat starchy veggies and fruits, which can add up. “A paleo diet can contain a number of carbs ranging from keto to normal carb levels,” says Spritzler. A benefit of a paleo eating plan is it emphasizes whole, unprocessed foods, she says. It can feel meat-heavy if you normally prefer a more plant-based diet. To make sure it stays low-carb, focus on vegetables that fall naturally lower on the carb spectrum, like cucumbers, tomatoes, zucchini, and peppers.
There are a lack of studies on the paleo diet as a whole, and it’s unclear how effective a low-carb version would be. But in general, a paleo diet may help you lose weight, reduce belly fat, and lower blood pressure and lipid levels, according to some studies. The downside, say researchers, is that the trials evaluating the diet are short-term and not high-quality; it’s also 10 percent more expensive compared with a regular diet and puts you at risk for calcium deficiency, note the researchers.
Whole30 is another diet (which bills itself as more of a program) that’s not specifically designed to be low in carbs. For 30 days, you’re asked to eat only meat, seafood, veggies, fruits, and fats, and stay away from added sugar of any kind — alcohol, grains, legumes, and dairy.
It can be a radical approach for someone who’s used to eating the standard American diet — which is low in fruits and veggies and high in added sugar and fat — and it may help you lose weight, says Spritzler, adding that the freedom to eat as many carbs as you want may make it a poor fit for people with type 2 diabetes. Because this is designed as a short-term challenge, it’s supposed to be tough. You have to weigh your stick-to-it-iveness before you start, and then plan out what you’re going to do after the 30 days are up.
8. Low-Carb Mediterranean Diet
This one wins big points for health from Spritzler. “I personally feel this is the ideal diet to follow, as it delivers all the benefits of both a Mediterranean and low-carb diet,” she says. The benefits of a Mediterranean diet are vast, as research has shown that this style of eating is associated with a lower risk of developing or dying from cardiovascular disease.
The difference from other low-carb diets is that you’re going to swap saturated fats for unsaturated fats — a plus if you have type 2 diabetes, which leaves you more at risk for heart disease, as the Centers for Disease Control and Prevention (CDC) notes, or if you have a personal or family history of heart disease yourself, per the Mayo Clinic. That means rather than butter, cheese, and cream, you’re eating olive oil, fatty fish, nuts, seeds, and avocado as your main sources of fat.
The big pro to this diet is that it’s very heart-friendly; the con is that for some people, the lure of a low-carb diet is often the ability to eat highly palatable foods, like bacon and cheese. Research analyzing the benefits of a low-carb Mediterranean diet on diabetes suggests keeping carbohydrates to no more than 50 percent of your daily calories and getting at least 30 percent of your calories from fat, focusing on vegetables and whole grains as carb sources.
9. Dukan Diet
On this diet, you’ll be led through four phases. For the first phase, you’ll focus on foods high in protein and then add vegetables back in, followed by gradually introducing more carb-containing foods, like fruits and whole-grain bread, plus an allowance of two celebration meals per week. In the final phase, you’ll aim to maintain your weight loss results by eating foods from all food groups, supplementing with oat bran, and fitting in fitness daily.
Among the cons of this diet are that there are a lot of rules to follow and you have to eat a lot of protein. According to one study, the high-protein initial phase of the diet could increase the risk of developing kidney stones as an unpleasant side effect. If you’ve gotten kidney stones in the past, you will want to rethink trying out this diet, the authors of the study note.
10. The South Beach Diet
Unlike some of the other types of low-carb diets, which focus on health benefits, this one bills itself as a pure weight loss diet. While you focus more on lean protein and healthy fats, the Mayo Clinic notes, the South Beach Diet isn’t necessarily a strict low-carb diet. In fact, you eat “good carbs” — especially after the first phase.
On the diet, you can get frozen and ready-to-eat South Beach Diet meals, along with some meals you make on your own. They also encourage you to buy South Beach Diet–branded snacks. The upside is that they’ll tell you what to eat all day, and there’s little cooking involved (great if you hate your kitchen); the downside is that you have to buy your food through them, and the choices can become limiting. Plus, when you’re buying packaged foods, you’re not getting the full nutritional benefit you would from eating whole foods.
Then, there’s the fact that this may lack nutrients. One study analyzed several popular diet plans, South Beach being one of them, and concluded that the diet is extremely low-calorie (about 1,200 calories) and did not offer a sufficient source of 21 out of 27 essential nutrients analyzed, including vitamin D, vitamin E, iron, magnesium, and zinc.
11. Carb Cycling
In this twist on a low-carb diet, carb cycling means that you alternate low-carb days (50 to 150 g of carbs) with high-carb days (up to 400 g of carbs), according to the American Council on Exercise. The number of high- and low-carb days differs according to the specific plan you’re following. (Keto cycling, for example, is a way of varying carb amounts on the keto diet.) “The main benefit is that being able to have higher-carb days helps people tolerate the lower-carb days and also have more fuel for their workouts, which is why it’s popular with athletes and certain types of training,” says Hultin. The catch is that the low-carb days can make you feel restricted, and then you overcompensate on the higher-carb days. “I’d prefer a more balanced, daily plan so that you don’t have to worry so much about calculating a specific intake every single day,” she says.
12. Zero-Carb Diet
If you look around the web, you’ll see that many people have taken on the challenge of a zero-carb diet, a diet that lacks research and involves eating only meat and fat. The controversial carnivore diet, where you eat only meat, is similar. The downside of this diet is that it can be exceptionally high in saturated fat and contains no fiber, something that helps digestion, and no vegetables or fruit, which provide critical vitamins, minerals, and antioxidants. Considering that experts recommend talking to your doctor even before going on a ketogenic diet — and this is a much more severe form — you need to consult a medical professional before attempting the zero-carb diet.